Method and apparatus for forming plastic-lined metal conduit

ABSTRACT

An apparatus for continuously forming a metal and plastic composite conduit having a metallic outer surface, cutting portions from the continuously formed conduit, and ejecting the cutoff portions from the apparatus.

I Umted States Patent [151 3,639,970 Larkin 1 Feb. 8, 1972 [54] METHODAND APPARATUS FOR 2,126,453 8/1938 Criley et a1 ..29/4l7 UX FORMINGPLASTIC-LINED METAL 2,888.954 6/1959 Gates ..l38/l37 CONDUIT 3,069,76312/1962 Reynolds ..29/477.7 X 3,168,910 2/1965 Galloway et al. ..138/l37[72] Inventor: Mark E. Larkin, Bartlesville, Okla.

[73] Assignee: Phillips Petroleum Company ima y mi'w Char|i T. MOOn 221Filed: Oct. 2, 1969 and 0mg [21] Appl. No.: 863,198 [57] ABSTRACT Anapparatus for continuously forming a metal and plastic [52] [LS-Cl...29/4ll, 29/33 D, 29/4741, composite conduit having a metallic outersurface, cutting 29/477'7, 138/151 264/176 285/55 portions from thecontinuously formed conduit, and ejecting [51] Int. Cl ..B23p 17/00 thecutoff portions from the apparatus [58] Field of Search ..29/429, 474.1,411, 33.4, 33 D,

29/4777, 417; 138/137, 140, 151, 158; 264/176; 3 Cl i 3 D ing Figures[56] References Cited UNITED STATES PATENTS Allen ..138/l40 METHOD ANDAPPARATUS FOR FORMING PLASTIC- LINED METAL CONDUIT This inventionrelates to an apparatus for forming a composite metal and plasticconduit having a metallic outer surface and a plastic inner surface. Inanother aspect, this invention relates to an apparatus for continuouslyforming a composite metal and plastic conduit from an extruded plastictube and a flat metallic tape.

Plastic-lined tubing or conduit is principally formed by one of twomethods. In the first method, metallic conduit is internally coated byrolling or spraying a plastic film onto the inner surface. The coatingis thereafter cured by heating to high temperatures or by other meansknown in the art. The resultant composite conduit generally has thedisadvantages of being easily damaged owing to the relative thinness ofthe plastic, poorly adapted to subsequent insertions of metal objectsinto the conduit in contact with the plastic, and often incompletelycoated over the inner surface. In the second methodrelatively shortlengths of plastic tubing are inserted into a metallic conduit to form acomposite metallic and plastic conduit. Owing to the fact that theplastic tubing to be inserted must be considerably smaller in outsidediameter than the inside diameter of the metallic conduit to preventundue friction during the insertion operations, the resultant parts ofthe composite conduit are not satisfactorily maintained together to forman integral conduit. Slippage of the plastic tubing within the metalconduit can damage the plastic or allow leakage of corrosive fluids pastthe plastic conduit. The frictional forces generated during plastictubing insertion also limits the maximum length of the composite conduitand often causes damage to the plastic tubing and waste.

Both of the principal methods of forming a composite metallic andplastic conduit require a great deal of labor and supervision, result inlarge amounts of waste, are limited to producing short length conduits,and comprise a plastic inner shell that is of less than desirabledurability.

It is therefore an object of this invention to provide an ap paratus forconstructing an improved composite metallic and plastic conduit. Anotherobject is to provide an apparatus for forming a continuous conduit ofthe above-described type. Yet another object of this invention is toprovide an apparatus that will automatically, continuously producecomposite conduit of the above-described type with the utilization ofless supervision and with decreased waste. A further object of thisinvention is to provide an apparatus for producing a plurality ofcomposite conduits of the above-described type, each having apreselected length. Other aspects, objects, and advantages of thepresent invention will become apparent from a study of the disclosure,the appended claims, and the drawing.

The drawings are diagrammatic views of the apparatusof this invention.

FIG. I is a diagrammatic front view of the apparatus of this invention.

FIG. 2 is a plan view of a portion of the conveying means of theapparatus and FIG. 3 is a sectional view of the conveying means takenalong line 33 of FIG. 2.

FIG. I shows a conventional plastic extruder 2 having a die 4 forforming a plastic conduit 6. A metal conduit former 8 is positioned inthe pathway of the plastic conduit issuing from the extruder 2 andpreferably spaced a distance from said extruder 2 to provide for coolingof the plastic conduit 6. The conduit former 8 has inlet and outlet endsl0, 12. Plastic conduit 6 issuing from the extruder 2 and continuousmetallic tape 14 issuing from a tape reservoir 16 enter the inlet end ofthe conduit former 8, pass through the former 8, and discharge from theoutlet end 12 of said former 8. A sealing means 18 such as solderingapparatus, adhesive-applicating apparatus, metal-crimping apparatus, orthe like, is positioned adjacent the outlet end 12 of the former 8 andthe abutting edges of the tape 14 in the encompassing position of thetape about the plastic conduit for continuously sealing the edges of thetape 14.

It is preferred that the sealing means be positioned as near aspractical to the outlet end 12 of the former 8. If the sealing means istoo far removed from the outlet end 12 of the former 8 the abuttingedges tend to spring back toward their original flat position therebypermitting the edges of the tape 14 to become spaced one from the otherand result in a seal of reduced quality. A support means 20 ispreferably positioned adjacent the outlet end 12 of the former 8 tomaintain the composite conduit 22 issuing therefrom against lateralmovement.

A cutter 24 having a cutter element 26 is positioned adjacent thesealing means 18 for cutting the composite conduit 22 at preselectedlocations. The cutting element 26 is preferably a rotating circular sawdriven by an electric motor 28. The cutting element 26 is attached to afirst end 30 of a power means 32, preferably a hydraulic cylinder, formoving the cutting element in a transverse direction relative to thecomposite conduit 22. The power means 32 is attached at the second end34 to a track 36 for longitudinal movement of the cutting element 26along the longitudinal, axis of the composite conduit 22. A conveyingmeans 38 is positioned adjacent the cutting elements 26 for receivingthe composite conduit 22 and maintaining said conduit 22 against lateralmovement.

Referring to FIGS. 2 and 3, conveying means 38 has a plurality ofopposed, downwardly and inwardly extending rollers 40, each attached bya separate bearing 42 to the respective first and second sides 44, 46 ofa supporting frame 48 of the conveying means 38. The inward ends 50 ofthe rollers 40 terminate adjacent one another at a position lower inelevation than the composite conduit 22 issuing from the former 8 andthe roller bearings 42 thereby forming a Vshaped supporting structurefor the composite conduit 22. By so constructing a V-shaped conveyingmeans, lateral movement of the composite conduit 22 is prevented byimpingement of the rollers upon said conduit 22.

In order to provide for movement of a cutoff section of compositeconduit 22 from the apparatus for further handling, it is preferred thatthe conduit section be moved laterally, thereby conserving space. Inorder to accomplish lateral movement of a conduit from the conveyingmeans the lower end 52 of the first side 44 of the frame 48 is pivotallyattached to a fixed structure 54. The second side 46 of the frame 48 isattached to a power source 56, preferably a hydraulic cylinder, forpivoting the conveying means 38 between a first position at which theframe 48 and associated roller 40 are supporting the conduit 22 and asecond position at which the frame 48 and roller 40 are inclinedrelative to the first position.

In the operation of this invention, a plastic conduit continuouslyissues from the die 4 of the extruder 2 and passes into the conduitformer 8. Within the former 8 a flat continuous metallic tape 14 isdeflected to entirely encompass the plastic conduit 6. Although it ispreferred that the plastic conduit 6 and the composite conduit 22 be ofa round tubular shape, other shaped conduits such as square,rectangular, triangular, etc., can be formed with the apparatus of thisinvention. In order to provide a relatively smooth, fluidtight seal itis also preferred that the conduit former 8 wraps the metallic tapeabout the plastic conduit with the edges of the tape in abuttingrelationship thereby forming a longitudinal seam. Conduit forms whichcrimp or fold the edges into fixed contact one with the other can alsobe used in this invention.

As the metallic tape 14 is continuously attached to the plastic conduit,the resulting composite conduit 22 continuously moves outwardly from theformer 8 adjacent the cutter 24. After a preselected length of thecomposite conduit 22 has been formed and portions thereof have beenextended onto the conveying means 38 in supporting relationship relativethereto, the electric motor 28 is actuated to energize the cuttingelement 26 and the power source 56 is actuated to transversely move thecutting element from a first position at which the cutting element 26 isspaced from the conduit 22 to a second position at which a portion ofthe cutting element 26 extends traversely through and beyond the conduit22 thereby cutting a portion of the conduit 22 from the continuouslyforming conduit. During movement of the cutting element 26 from thefirst to the second position, the power source 32 and associatedelectric motor 28 and cutting element 26 are moved along the track 36preferably by a separate electric motor 58. The cutting element is movedalong the track in a pathway parallel to the conduit and in the samedirection and at the same rate of the travel that said conduit 22 ismoving relative to the conduit former 8. The separate electric motor 58is preferred for movement of the cutter 24 along the track 36 in orderto assure that increased power requirements from cutting the conduit donot influence the rate of travel of the cutter 24. It is necessary thatthe cutter move longitudinally relative to the conduit 22 being cut inorder that the cutting element 26 does not bind within the cut and thatthe apparatus can continuously form conduit during cutting of theconduit into preselected lengths. After cutting of the conduit 22 theelectric motor28 associated with the cutting means is deenergized, thepower means 32 moves the cutting element in an opposed direction, andthe electric motor 58 returns the cutter 24 along the track 36 for theinitiation of a new cycle. After severance of a portion of the compositeconduit 22 by the cutting element 26, the power source 56 of the frame48 pivots the frame 48 to discharge the severed conduit portion andreturns said frame 48 for receiving conduit 22 issuing from the former8.

It should be understood that the preferred cutting means described abovefor severing the moving conduit can be of other construction withoutdeparting from this invention. Other modifications and alterations ofthis invention will become apparent to those skilled in the art from theforegoing discussion and accompanying drawing, and it should beunderstood that this invention is not to be unduly limited thereto.

What is claimed is:

1. An apparatus-for forming a composite metal and plastic conduit havinga metal outer surface and a plastic inner surface, comprising:

an extruder having a die for continuously extruding a plastic conduit;

a metal conduit former having inlet and outlet ends positioned in thepathway of the plastic conduit issuing from the extruder forcontinuously receiving a metallic tape and the plastic conduit from theextruder, wrapping the metallic tape about the entire outer surface ofsaid plastic conduit to produce abutting tape edges, and sealing saidabutting edges of the metallic tape;

a cutter having a cutting element and being positioned adjacent theoutlet end of the metal conduit former and being intermittently movablerelative to the conduit issuing from said conduit former for cutting theconduit at preselected intervals;

a plurality of opposed downwardly and inwardly extending rollerspositioned at a lower elevation from the cutter for maintaining theconduit from lateral movement during cutting operations;

movable frame attached to the plurality of rollers, said frame andassociated rollers being movable between a first position at which theframe and rollers are supporting the conduit and a second position atwhich the frame and rollers are inclined relative to the first positionfor discharging the conduit from the rollers; and

power means attached to the frame for moving the frame from the first tothe second position in response to cutting of the conduit.

2. An apparatus, as set forth in claim 1, wherein the metal conduitfonner wraps the metal tape about the plastic conduit with edges of thetape in abutting relationship and a sealing means positioned adjacentthe outlet of the conduit former and adjacent the abutting edges of thetape for continuously sealing the ed es of the tape one to the other.

3. A metho for forming a composite metal and plastic conduit having ametal outer surface and a plastic inner surface, comprising:

extruding a plastic conduit from an extruder; passing the plasticconduit into a metal conduit former; deflecting a metallic tape aboutthe outer surface of the conduit with the edges of said tape in abuttingrelationship and sealing said abutting edges to form a compositeconduit; intermittently cutting in two the continuous composite conduit;and ejecting the cutoff portion of the conduit from the pathway of thecontinuously fonning composite conduit.

1. An apparatus for forming a composite metal and plastic conduit havinga metal outer surface and a plastic inner surface, comprising: anextruder having a die for continuously extruding a plastic conduit; ametal conduit former having inlet and outlet ends positioned in thepathway of the plastic conduit issuing from the extruder forcontinuously receiving a metallic tape and the plastic conduit from theextruder, wrapping the metallic tape about the entire outer surface ofsaid plastic conduit to produce abutting tape edges, and sealing saidabutting edges of the metallic tape; a cutter having a cutting elementand being positioned adjacent the outlet end of the metal conduit formerand being intermittently movable relative to the conduiT issuing fromsaid conduit former for cutting the conduit at preselected intervals; aplurality of opposed downwardly and inwardly extending rollerspositioned at a lower elevation from the cutter for maintaining theconduit from lateral movement during cutting operation; a movable frameattached to the plurality of rollers, said frame and associated rollersbeing movable between a first position at which the frame and rollersare supporting the conduit and a second position at which the frame androllers are inclined relative to the first position for discharging theconduit from the rollers; and power means attached to the frame formoving the frame from the first to the second position in response tocutting of the conduit.
 2. An apparatus, as set forth in claim 1,wherein the metal conduit former wraps the metal tape about the plasticconduit with edges of the tape in abutting relationship and a sealingmeans positioned adjacent the outlet of the conduit former and adjacentthe abutting edges of the tape for continuously sealing the edges of thetape one to the other.
 3. A method for forming a composite metal andplastic conduit having a metal outer surface and a plastic innersurface, comprising: extruding a plastic conduit from an extruder;passing the plastic conduit into a metal conduit former; deflecting ametallic tape about the outer surface of the conduit with the edges ofsaid tape in abutting relationship and sealing said abutting edges toform a composite conduit; intermittently cutting in two the continuouscomposite conduit; and ejecting the cutoff portion of the conduit fromthe pathway of the continuously forming composite conduit.